Microelectrode arrays contain multiple projections with an electrode through which neural signals can be measured, monitored, and/or stimulated. Electrodes on the array change the voltage environment around the neurons and can induce or receive an electric current from surrounding bioelectrical activity. The proximity of the electrode to neurons dictates the strength of signals and ultimately the number of signals that actually reach neurons which affects the overall efficacy of the microelectrode array.
Given the small scale of microelectrode arrays, manufacturing difficulties have limited the number of electrodes that can be placed on each projection. In the case of three-dimensional Utah microelectrode arrays a single electrode is oriented at the tip of each projection in the array. These electrodes are electrically isolated from one another and serve as independent electrodes. The placement of the electrodes at the tip of each projection measures, monitors, and/or stimulates neurons proximate the tip of the projection.